Engine Idle problem on 1999 Jeep Grand Cherokee

Idle speed goes up and down. I took the car to the dealer and they replaced the idle air control motor. It worked for a day and then it started doing the same up and down speed at idle. The idle speed goes up and down. I took it back again and they said that they had to replace the idle air control motor agai because the part must be bad. It did the same thing after a couple days and now it is even worse. The idle goes from 600 to sometimes as high as 1200 RPM and then goes back down. Then it will go back up. Sometimes when you put the car in park, the engine speed will go up to 1200 to 1500 RPM and then go to 1000 and after a while it goes to 600 or 700. This has me a little upset and it is very irritating. The dealer told me the last time they replaced the idle air control motor, they were online with Chrysler techs. I really doubt that, if it was true I would think the problem should be fixed. Not to mention it has cost me $255.35 parts and labor. Not to mention my time. Help!!!!!

Sounds like the dealer tech is not taking the time to diagnose the problem and is possibly just replacing the part, but it's hard to know for sure. I would take it back and try to see if they have a shop foreman, and have that person look at the car. Shops are full of techs of various abilities, and you need to demand to have the best tech look at this problem. They need to step up and take care of this for you. Hopefully they will still be in business next week! Good Luck!